U.S. patent application number 16/126624 was filed with the patent office on 2019-05-23 for optical member and display including the same.
The applicant listed for this patent is Samsung Display Co. Ltd.. Invention is credited to Seong Yong HWANG, Sang Won LEE, Hye Eun PARK, Sung Kyu SHIM.
Application Number | 20190154901 16/126624 |
Document ID | / |
Family ID | 66532918 |
Filed Date | 2019-05-23 |
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United States Patent
Application |
20190154901 |
Kind Code |
A1 |
LEE; Sang Won ; et
al. |
May 23, 2019 |
OPTICAL MEMBER AND DISPLAY INCLUDING THE SAME
Abstract
An optical member includes a light guide plate in which light
incident thereto is propagated, including: an emission surface
through which propagated light exits the light guide plate, a light
incident side surface through which the light is incident to the
light guide plate, and an inclined edge surface connecting the
emission and light incident side surfaces to each other; and a
wavelength conversion layer to which exited light from the light
guide plate is incident and which converts a wavelength of the
exited light, disposed facing the emission surface of the light
guide plate. The inclined edge surface and emission surfaces define
a boundary therebetween, and a side surface of the wavelength
conversion layer which is closest to the light incident side
surface is further from the light incident side surface than the
boundary between the inclined edge surface and the emission
surface.
Inventors: |
LEE; Sang Won; (Seoul,
KR) ; HWANG; Seong Yong; (Hwaseong-si, KR) ;
PARK; Hye Eun; (Hwaseong-si, KR) ; SHIM; Sung
Kyu; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co. Ltd. |
Yongin-si |
|
KR |
|
|
Family ID: |
66532918 |
Appl. No.: |
16/126624 |
Filed: |
September 10, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 2001/133614
20130101; G02F 1/1336 20130101; G02B 6/0031 20130101; G02B 6/0023
20130101; G02B 6/002 20130101; G02B 6/005 20130101; G02B 6/0043
20130101 |
International
Class: |
F21V 8/00 20060101
F21V008/00; G02F 1/13357 20060101 G02F001/13357 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 20, 2017 |
KR |
10-2017-0155054 |
Claims
1. An optical member comprising: a light guide plate in which light
incident thereto is propagated, including: an emission surface
through which propagated light exits the light guide plate, a light
incident side surface through which the light is incident to the
light guide plate, and an inclined edge surface connecting the
emission surface and the light incident side surface to each other;
and a wavelength conversion layer to which exited light from the
light guide plate is incident and which converts a wavelength of
the exited light, disposed facing the emission surface of the light
guide plate, wherein the inclined edge surface and the emission
surface of the light guide plate define a boundary therebetween,
and a side surface of the wavelength conversion layer which is
closest to the light incident side surface of the light guide plate
is further from the light incident side surface than the boundary
between the inclined edge surface and the emission surface of the
light guide plate.
2. The optical member of claim 1, wherein the inclined edge surface
of the light guide plate is exposed to outside the optical
member.
3. The optical member of claim 2, wherein an inclination angle of
the inclined edge surface of the light guide plate with respect to
the emission surface of the light guide plate is about 6.degree. to
about 20.degree..
4. The optical member of claim 3, wherein a distance from the light
incident side surface of the light guide plate to the boundary
between the inclined edge surface and the emission surface of the
light guide plate is about 0.84 millimeter or more.
5. The optical member of claim 4, wherein the distance from the
light incident side surface of the light guide plate to the
boundary between the inclined edge surface and the emission surface
of the light guide plate is about 1 millimeter or more.
6. The optical member of claim 1, wherein the light guide plate
includes an inorganic material.
7. The optical member of claim 6, further comprising a refractive
layer disposed between the emission surface of the light guide
plate and the wavelength conversion layer, wherein a refractive
index of the refractive layer is smaller than that of the light
guide plate including the inorganic material, and a difference
between the refractive index of the light guide plate including the
inorganic material and the refractive layer is about 0.2 or
more.
8. The optical member of claim 7, wherein an inclination angle of
the inclined edge surface of the light guide plate with respect to
the emission surface of the light guide plate is about 6.degree. to
about 20.degree..
9. The optical member of claim 1, wherein with respect to the
emission surface of the light guide plate, an inclination angle of
the side surface of the wavelength conversion layer is identical to
an inclination angle of the inclined edge surface of the light
guide plate.
10. The optical member of claim 9, wherein the side surface of the
wavelength conversion layer is coplanar with the inclined edge
surface of the light guide plate.
11. The optical member of claim 1, further comprising: a refractive
layer disposed between the emission surface of the light guide
plate and the wavelength conversion layer, a refractive index of
the refractive layer being smaller than that of the light guide
plate; and a passivation layer through which converted light from
the light conversion layer exits the optical member, disposing the
wavelength conversion layer between the refractive layer and the
passivation layer.
12. The optical member of claim 11, wherein a side surface of the
refractive layer and a side surface of the passivation layer which
are closest to the light incident side surface of the light guide
plate is further from the light incident side surface than the
boundary between the inclined edge surface and the emission surface
of the light guide plate.
13. The optical member of claim 12, wherein with respect to the
emission surface of the light guide plate, an inclination angle of
the side surface of the refractive layer, an inclination angle of
the side surface of the wavelength conversion layer, and an
inclination angle of the side surface of the passivation layer are
identical to an inclination angle of the inclined edge surface of
the light guide plate.
14. The optical member of claim 1, further comprising a light
adjustment member with which a path of light is adjusted to be
incident into the light guide plate, the light adjacent member
disposed on the inclined edge surface of the light guide plate.
15. The optical member of claim 14, wherein the light adjustment
member disposed on the inclined edge surface of the light guide
plate extends therefrom to cover the side surface of the wavelength
conversion layer.
16. The optical member of claim 15, wherein a refractive index of
the light adjustment member is equal to or greater than a
refractive index of the light guide plate.
17. The optical member of claim 15, wherein a side surface of the
light adjustment member extends from and is coplanar with the light
incident side surface of the light guide plate to define a
continuous light incident side surface of the optical member.
18. An optical member comprising: a light guide plate in which
light incident thereto is propagated, including: an emission
surface through which propagated light exits the light guide plate,
a light incident side surface through which the light is incident
to the light guide plate, and an inclined edge surface connecting
the emission surface and the light incident side surface to each
other; a wavelength conversion layer to which exited light from the
light guide plate is incident and which converts a wavelength of
the exited light, disposed facing the emission surface of the light
guide plate; and a light adjustment member with which a path of
light is adjusted to be incident into the light guide plate,
disposed facing the inclined edge surface of the light guide plate
and spaced apart from the wavelength conversion layer, wherein a
first region of the light guide plate extends from the light
incident side surface thereof to an end of the light adjustment
member furthest from the light incident side surface, a second
region of the light guide plate extends from the first region in a
direction away from the light incident side surface and includes
the wavelength conversion member facing the emission surface of the
light guide plate, and a thickness of the light adjustment member
with respect to the light guide plate is maximum at a boundary
between the first region and the second region of the light guide
plate.
19. The optical member of claim 18, wherein a refractive index of
the light adjustment member is equal to or greater than a
refractive index of the light guide plate.
20. An optical member comprising: a light guide plate in which
light incident thereto is propagated, including: an emission
surface through which propagated light exits the light guide plate,
and a light incident side surface through which the light is
incident to the light guide plate; a refractive layer which is
disposed facing the emission surface of the light guide plate and
receives light exited therethrough, a refractive index of the
refractive layer being smaller than that of the light guide plate;
a wavelength conversion layer to which light from the refractive
layer is incident and which converts a wavelength of the light
incident thereto, disposing the refractive layer between the
emission surface of the light guide plate and the wavelength
conversion layer; a passivation layer to which light from the
wavelength conversion layer is incident and through which light
exits from the optical member, disposed covering a side surface of
the refractive layer and a side surface of the wavelength
conversion layer; and an angle filter disposed on the light
incident side surface of the light guide plate, wherein the angle
filter reflects light having an incident angle equal to or larger
than a first angle with respect to the light incident side surface
of the light guide plate and passes light having an incident angle
smaller than the first angle.
21. The optical member of claim 20, wherein the first angle is
about 54.degree..
Description
[0001] This application claims priority to Korean Patent
Application No. 10-2017-0155054 filed on Nov. 20, 2017 and all the
benefits accruing therefrom under 35 U.S.C. .sctn. 119, the
contents of which in their entirety are herein incorporated by
reference.
BACKGROUND
1. Field
[0002] Exemplary embodiments relate to an optical member and a
display device including the same.
2. Description of the Related Art
[0003] A liquid crystal display ("LCD") device displays an image by
receiving light from a backlight assembly. Some backlight
assemblies include a light source and a light guide plate. The
light guide plate receives light from the light source and guides
the light toward a display panel of the LCD device.
[0004] Generally, a point light source such as a light-emitting
diode ("LED") is frequently used as the light source within
backlight assemblies. However, a point light source emits scattered
light, such that total reflection of light within a light guide
plate is determined by an angle of light entering the light guide
plate.
SUMMARY
[0005] One or more exemplary embodiment of the invention provides
an optical member having an excellent light guide function.
[0006] It should be noted that features of the present disclosure
are not limited to the above-described object, and other features
of the present disclosure will be apparent to those skilled in the
art from the following descriptions.
[0007] According to some exemplary embodiments, an optical member
includes a light guide plate in which light incident thereto is
propagated, including: an emission surface through which propagated
light exits the light guide plate, a light incident side surface
through which the light is incident to the light guide plate, and
an inclined edge surface connecting the emission surface and the
light incident side surface to each other; and a wavelength
conversion layer to which exited light from the light guide plate
is incident and which converts a wavelength of the exited light,
disposed facing the emission surface of the light guide plate. The
inclined edge surface and the emission surface of the light guide
plate define a boundary therebetween, an a side surface of the
wavelength conversion layer which is closest to the light incident
side surface of the light guide plate is further from the light
incident side surface than the boundary between the inclined edge
surface and the emission surface of the light guide plate.
[0008] According to some exemplary embodiments, an optical member
includes a light guide plate in which light incident thereto is
propagated, including: an emission surface through which propagated
light exits the light guide plate, a light incident side surface
through which the light is incident to the light guide plate, an
inclined edge surface connecting the emission surface and the light
incident side surface to each other; a wavelength conversion layer
to which exited light from the light guide plate is incident and
which converts a wavelength of the exited light, disposed facing
the emission surface of the light guide plate; and a light
adjustment member with which a path of light is adjusted to be
incident into the light guide plate, disposed facing the inclined
edge surface of the light guide plate and spaced apart from the
wavelength conversion layer. A first region of the light guide
plate extends from the light incident side surface thereof to an
end of the light adjustment member furthest from the light incident
side surface, a second region of the light guide plate extends from
the first region in a direction away from the light incident side
surface and includes the wavelength conversion member facing the
emission surface of the light guide plate, and a thickness of the
light adjustment member with respect to the light guide plate is
maximum at a boundary between the first region and the second
region of the light guide plate.
[0009] According to some exemplary embodiments, an optical member
includes a light guide plate in which light incident thereto is
propagated, including: an emission surface through which propagated
light exits the light guide plate, and a light incident side
surface through which the light is incident to the light guide
plate; a refractive layer which is disposed facing the emission
surface of the light guide plate and receives light exited
therethrough, a refractive index of the refractive layer being
smaller than that of the light guide plate; a wavelength conversion
layer to which light from the refractive layer is incident and
which converts a wavelength of the light incident thereto,
disposing the refractive layer between the emission surface of the
light guide plate and the wavelength conversion layer; a
passivation layer to which light from the wavelength conversion
layer is incident and through which light exits from the optical
member, disposed covering a side surface of the refractive layer
and a side surface of the wavelength conversion layer, and an angle
filter disposed on the light incident side surface of the light
guide plate. The angle filter reflects light having an incident
angle equal to or larger than a first angle with respect to the
light incident side surface of the light guide plate and passes
light having an incident angle smaller than the first angle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other features of the present disclosure will
become more apparent by describing in detail exemplary embodiments
thereof with reference to the attached drawings, in which:
[0011] FIG. 1 is a perspective view of an exemplary embodiment of
an optical member of a display device according to the
invention;
[0012] FIG. 2 is a cross-sectional view taken along line II-II' of
FIG. 1;
[0013] FIG. 3 is a cross-sectional view of an exemplary embodiment
of region-specific threshold angles of a light guide plate within
an optical member according to the invention;
[0014] FIG. 4 is a cross-sectional view of paths of light at an
edge portion of a light guide plate within a conventional optical
member and an exemplary embodiment of an optical member according
to the invention;
[0015] FIGS. 5A and 5B are graphs showing experimental results of
amounts of light leakage caused by exemplary embodiments of an
inclination angle and a length of an edge surface in an optical
member according to the invention;
[0016] FIG. 6 is a graph showing experimental results of amounts of
light leakage at a boundary between exemplary embodiments of an
edge surface and an upper surface of a light guide plate in an
optical member according to the invention;
[0017] FIGS. 7 to 9 are cross-sectional views of modified exemplary
embodiments of an optical member according to the invention;
[0018] FIGS. 10 to 12 are cross-sectional views of other exemplary
embodiments of an optical member according to the invention;
[0019] FIG. 13 is a cross-sectional view of still another exemplary
embodiment of an optical member according to the invention; and
[0020] FIG. 14 is a cross-sectional view of an exemplary embodiment
of a display device according to the invention.
DETAILED DESCRIPTION
[0021] In the following description, for the purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of various exemplary embodiments.
It is apparent, however, that various exemplary embodiments may be
practiced without these specific details or with one or more
equivalent arrangements. In other instances, well-known structures
and devices are shown in block diagram form in order to avoid
unnecessarily obscuring various exemplary embodiments. Further,
various exemplary embodiments may be different, but do not have to
be exclusive. For example, specific shapes, configurations, and
characteristics of an exemplary embodiment may be implemented in
another exemplary embodiment without departing from the spirit and
the scope of the disclosure.
[0022] Unless otherwise specified, the illustrated exemplary
embodiments are to be understood as providing exemplary features of
varying detail of some exemplary embodiments. Therefore, unless
otherwise specified, the features, components, modules, layers,
films, panels, regions, aspects, etc. (hereinafter individually or
collectively referred to as "elements"), of the various
illustrations may be otherwise combined, separated, interchanged,
and/or rearranged without departing from the spirit and the scope
of the disclosure.
[0023] The use of cross-hatching and/or shading in the accompanying
drawings is generally provided to clarify boundaries between
adjacent elements. As such, neither the presence nor the absence of
cross-hatching or shading conveys or indicates any preference or
requirement for particular materials, material properties,
dimensions, proportions, commonalities between illustrated
elements, and/or any other characteristic, attribute, property,
etc., of the elements, unless specified. Further, in the
accompanying drawings, the size and relative sizes of elements may
be exaggerated for clarity and/or descriptive purposes. When an
exemplary embodiment may be implemented differently, a specific
process order may be performed differently from the described
order. For example, two consecutively described processes may be
performed substantially at the same time or performed in an order
opposite to the described order. Also, like reference numerals
denote like elements.
[0024] When an element is referred to as being related to another
element such as being "on," "connected to" or "coupled to" another
element, it may be directly on, connected to, or coupled to the
other element or intervening elements may be present. When,
however, an element is referred to as being related to another
element such as being "directly on," "directly connected to," or
"directly coupled to" another element, there are no intervening
elements present. To this end, the term "connected" may refer to
physical, electrical and/or fluid connection.
[0025] Although the terms "first," "second," etc. may be used
herein to describe various elements, these elements should not be
limited by these terms. These terms are used to distinguish one
element from another element. Thus, a first element discussed below
could be termed a second element without departing from the
teachings of the disclosure.
[0026] Spatially relative terms, such as "beneath," "below,"
"under," "lower," "above," "upper," "over," "higher," "side" (e.g.,
as in "sidewall"), and the like, may be used herein for descriptive
purposes, and, thereby, to describe one element's relationship to
another element(s) as illustrated in the drawings. Spatially
relative terms are intended to encompass different orientations of
an apparatus in use, operation, and/or manufacture in addition to
the orientation depicted in the drawings. For example, if the
apparatus in the drawings is turned over, elements described as
"below" or "beneath" other elements or features would then be
oriented "above" the other elements or features. Thus, the
exemplary term "below" can encompass both an orientation of above
and below. Furthermore, the apparatus may be otherwise oriented
(e.g., rotated 90 degrees or at other orientations), and, as such,
the spatially relative descriptors used herein interpreted
accordingly.
[0027] The terminology used herein is for the purpose of describing
particular embodiments and is not intended to be limiting. As used
herein, the singular forms, "a," "an" and "the" are intended to
include the plural forms as well, unless the context clearly
indicates otherwise. Moreover, the terms "comprises," "comprising,"
"includes," and/or "including," when used in this specification,
specify the presence of stated features, integers, steps,
operations, elements, components, and/or groups thereof, but do not
preclude the presence or addition of one or more other features,
integers, steps, operations, elements, components, and/or groups
thereof.
[0028] It is also noted that, as used herein, the terms
"substantially," "about," and other similar terms, are used as
terms of approximation and not as terms of degree, and, as such,
are utilized to account for inherent deviations in measured,
calculated, and/or provided values that would be recognized by one
of ordinary skill in the art. For example, "about" can mean within
one or more standard deviations, or within .+-.30%, 20%, 10% or 5%
of the stated value.
[0029] Various exemplary embodiments are described herein with
reference to sectional and/or exploded illustrations that are
schematic illustrations of idealized exemplary embodiments and/or
intermediate structures. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, exemplary embodiments
disclosed herein should not be construed as limited to the
particular illustrated shapes of regions, but are to include
deviations in shapes that result from, for instance, manufacturing.
In this manner, regions illustrated in the drawings are schematic
in nature and shapes of these regions may not illustrate the actual
shapes of regions of a device, and, as such, are not intended to be
limiting.
[0030] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
disclosure is a part. Terms, such as those defined in commonly used
dictionaries, should be interpreted as having a meaning that is
consistent with their meaning in the context of the relevant art
and will not be interpreted in an idealized or overly formal sense,
unless expressly so defined herein.
[0031] FIG. 1 is a perspective view of an optical member according
to an exemplary embodiment. FIG. 2 is a cross-sectional view taken
along line II-II' of FIG. 1. The optical member may be applied to
display devices which display an image with light provided from the
optical member, lighting fixtures which provide light within
various devices and the like.
[0032] Referring to FIGS. 1 and 2, an optical member 100 includes a
light guide plate 10, a (relatively) low refractive (index) layer
20, a wavelength conversion layer 30 disposed on the low refractive
layer 20, and a passivation layer 40 disposed on the wavelength
conversion layer 30. The light guide plate 10, the low refractive
layer 20, the wavelength conversion layer 30 and the passivation
layer 40 may be integrally coupled together.
[0033] The optical member 100 and components thereof may be
disposed in a plane defined by first and second directions crossing
each other. In FIG. 1, for example, the first and second directions
may be respectively extended along the relatively long and
relatively short sides of the optical member 100. A thickness of
the optical member 100 and components thereof may be defined in a
third direction which crosses each of the first and second
directions. In FIG. 2, for example, the third direction may be
vertical, while the first or second direction is horizontal.
[0034] The light guide plate 10 serves to guide light along a
travel path. The light travels within the light guide plate 10 to
be emitted therefrom to outside the light guide plate 10. The light
guide plate 10 may include an inorganic material. As an example,
the light guide plate 10 may include glass, but is not limited
thereto.
[0035] The light guide plate 10 may generally have a polygonal
pillar shape. A planar shape of the light guide plate 10 may be
rectangular in a top plan view, but is not limited thereto. In an
exemplary embodiment, the light guide plate 10 may have a hexagonal
pillar shape whose planar shape is rectangular. Such light guide
plate 10 may include an upper surface 10a, a lower surface 10b, and
four side surfaces 10s (10s1, 10s2, 10s3 and 10s4). Light
propagated within the light guide plate 10 may exit the light guide
plate 10 through the upper surface 10a thereof. The side surfaces
of the light guide plate 10 connect the upper and lower surfaces
10a and 10b to each other. In this specification and the
accompanying drawings, the four side surfaces are indicated as
"10s1," "10s2," "10s3" and "10s4" when it is necessary to
distinguish the four side surfaces from each other, but "10s" is
used to simply generally indicate a side surface. The label "10s"
may also be used to indicate a general collection of the side
surfaces which connect the upper and lower surfaces 10a and 10b to
each other.
[0036] In an exemplary embodiment, each of the upper surface 10a
and the lower surface 10b of the light guide plate 10 is positioned
in one plane. The plane in which the upper surface 10a is
positioned and the plane in which the lower surface 10b is
positioned are generally parallel to each other such that the light
guide plate 10 may have substantially the same thickness overall
across an entirety of the upper and/or lower surfaces 10a and 10b.
However, the planes in which the upper and lower surfaces 10a and
10b are positioned are not limited to planes parallel to each
other. Portions of the upper surface 10a and/or the lower surface
10b may be disposed in a plurality of planes. The planes in which
the upper and/or lower surfaces 10a and 10b are positioned may
intersect each other.
[0037] The light guide plate 10 may further include an inclined
edge surface 10r between the upper surface 10a and a side surface
10s and/or the lower surface 10b and the side surface 10s. The
upper/lower surface 10a/10b of the light guide plate 10 meets a
first side (end) of the edge surface 10r, and the side surface 10s
of the light guide plate 10 meets a second side (end) of the edge
surface 10r opposite to the first side thereof.
[0038] The edge surface 10r is inclined with respect to the
upper/lower surface 10a/10b and the side surface 10s. An
inclination angle .theta.1 of the edge surface 10r with respect to
the upper/lower surface 10a/10b may be about 6 degrees (.degree.)
to about 20.degree.. A length d1 of a section of a plane occupied
by the edge surface 10r, that is, the distance d1 from a boundary
between the edge surface 10r of the light guide plate 10 and the
upper/lower surface 10a/10b to the side surface 10s, may be about
0.84 millimeter (mm) or more, more preferably 1 mm or more. A
height h1 of the edge surface 10r, that is, the distance h1 from a
boundary between the edge surface 10r and the side surface 10s to
the upper/lower surface 10a/10b, may be determined by the
inclination angle .theta.1 of the edge surface 10r and the length
d1 of the edge surface 10r. Also, the height h1 and the inclination
angle .theta.1 of the edge surface 10r may be determined in
consideration of a planar area of a light incident surface 10s1
(e.g., product of a dimension thereof in the vertical direction and
a dimension thereof extended into the page of FIG. 2) of the light
guide plate 10. In other words, a minimum total planar area of the
light incident surface 10s1 of the light guide plate 10 may be
disposed or formed to be larger than a maximum total planar area of
a light emission window of a light source 400 (member), and the
height h1 and the inclination angle .theta.1 formed by the edge
surfaces 10r may be determined in consideration of the total planar
area of the light incident surface 10s1. The light incident surface
10s1 and the one or more edge surface 10r may collectively define a
side surface of the light guide plate 10.
[0039] The one or more edge surface 10r may serve to reduce or
effectively prevent damage of the light guide plate 10 from
external impact thereto by reducing the sharpness of a transition
from the upper/lower surface 10a/10b and the light incident surface
10s1 at an edge portion of the light guide plate 10. Also, the one
or more edge surface 10r adjusts a path of light at the light
incident surface 10s1 of the light guide plate 10 to efficiently
cause total reflection in the light guide plate 10 and to reduce or
effectively prevent light leakage at the light incident surface
10s1. This will be described below with reference to FIGS. 3 to
6.
[0040] In cross-section the one or more edge surface 10r may be a
flat surface disposed at an incline, or may be a curved surface
disposed at an incline (refer to edge surface 11r of an optical
member 101 of FIG. 7).
[0041] However, the present disclosure is not limited to a case in
which an edge surface is defined for the light guide plate 10. As
shown in FIGS. 10 and 13, planes in which upper surfaces 14a and
17a and/or lower surfaces 14b and 17b of light guide plates 14 and
17 are positioned may be inclined by about 90.degree. with respect
to planes in which respective side surfaces 14s and 17s are
positioned. A case in which the light guide plate 10 includes the
edge surfaces 10r will be described below.
[0042] In an application example of the optical member 100, the
light source 400 may be disposed adjacent to at least one side
surface 10s of the light guide plate 10, to define a light incident
side surface thereof. Although drawings show a case in which a
point light source such as a light-emitting diode ("LED") 410 is
provided in plurality mounted on a single one printed circuit board
("PCB") 420 to be disposed adjacent to the side surface 10s1
positioned at one relatively long side of the light guide plate 10,
a position of the plurality of LED light sources 410 is not limited
thereto. In an exemplary embodiment, for example, the plurality of
LED light sources 410 may be disposed adjacent to both the side
surfaces 10s1 and 10s3 at the relatively long sides of the optical
member 100, and/or may be disposed adjacent to both or one of the
side surfaces 10s2 and 10s4 of the relatively short sides of the
optical member 100.
[0043] In the exemplary embodiment of FIG. 1, the side surface 10s1
at a first relatively long side of the light guide plate 10 to
which the light source 400 is adjacently disposed is the light
incident surface (indicated as "10s1" in drawings for convenience
of description). Light of the light source 400 is directly incident
to the light incident surface 10s1, and the side surface 10s3 at a
second relatively long side opposite to the first relatively long
side is a light-facing surface (indicated as "10s3" in drawings for
convenience of description).
[0044] A scattering pattern 70 may be disposed in plurality at the
lower surface 10b of the light guide plate 10. The scattering
pattern 70 serves to change an angle of light which travels within
the light guide plate 10 by total reflection and to project the
light from the light guide plate 10.
[0045] In an exemplary embodiment, the scattering pattern 70 may be
disposed or formed as a portion of the light guide plate 10 which
is protruded from or recessed into a main body thereof relative to
the upper and/or lower surface 10a and 10b thereof. In an exemplary
embodiment, for example, a groove may be disposed or formed
recessed from the lower surface 10b of the light guide plate 10 to
function as the scattering pattern 70.
[0046] In another exemplary embodiment, the scattering pattern 70
may be provided as a separate layer or pattern relative to the
light guide plate 10. In an exemplary embodiment, for example, a
print pattern or a pattern layer including a protruding pattern
and/or a groove pattern separate from the light guide plate 10 may
be disposed or formed on the lower surface 10b of the light guide
plate 10 to function as the scattering pattern 70.
[0047] A density of disposition of the scattering pattern 70
provided in plurality may be controlled differently regions of the
light guide plate 10. In an exemplary embodiment, for example, the
density of disposition of scattering patterns 70 may be relatively
low in a region of the light guide plate 10 adjacent to the light
incident surface 10s1 through which a relatively large amount of
light travels into the light guide plate 10. The density of
disposition of scattering patterns 70 may be relatively high in a
region of the light guide plate 10 adjacent to the light-facing
surface 10s3 through or at which a relatively small amount of light
travels.
[0048] The low refractive layer 20 is disposed on the upper surface
10a of the light guide plate 10 through which light is emitted from
the light guide plate 10. The low refractive layer 20 is interposed
between the light guide plate 10 and the wavelength conversion
layer 30 and helps with total reflection of light within the light
guide plate 10. The low refractive layer 20 may be disposed in an
active area of the light guide plate 10 at which light exits from
the optical member 100. In an exemplary embodiment, for example,
the active area of the light guide plate 10 may corresponding to a
display area of a display panel at which an image is displayed with
light from the optical member 100, without being limited thereto.
The active area of the light guide plate 10 may correspond to a
light incident area of a component external to the optical member
100 without being limited thereto.
[0049] More specifically, it is desirable to provide effective
total internal reflection at the upper surface 10a and the lower
surface 10b of the light guide plate 10 so that light is
efficiently guided by the light guide plate 10 from the light
incident surface 10s1 thereof to the light-facing surface 10s3
thereof. One of the conditions for total internal reflection in the
light guide plate 10 is that a refractive index of the light guide
plate 10 is higher than that of a medium having an optical
interface with the light guide plate 10.
[0050] In an exemplary embodiment, for example, the light guide
plate 10 may include glass having a refractive index of about 1.5.
In this case, when the upper surface 10a of the light guide plate
10 has an optical interface with an air layer, light incident at an
angle of larger than about 42.degree., which is a threshold angle
.theta.t1 (refer to FIG. 3) of the light guide plate 10, may be
totally reflected.
[0051] On the other hand, when optical function layers having
relatively high refractive indices are stacked on the upper surface
10a of the light guide plate 10, a threshold angle of the light
guide plate 10 becomes too large for sufficient total reflection.
The wavelength conversion layer 30 stacked on the upper surface 10a
of the light guide plate 10 generally has a refractive index of
about 1.5. When the wavelength conversion layer 30 is directly
stacked on the upper surface 10a of the light guide plate 10 having
a refractive index of about 1.5, achieving total reflection at the
upper surface 10a of the light guide plate 10 may be difficult.
[0052] The low refractive layer 20, which is interposed between the
light guide plate 10 and the wavelength conversion layer 30 and has
an interface with the upper surface 10a of the light guide plate
10, has a lower refractive index than that of the light guide plate
10 so that total reflection occurs at the upper surface 10a of the
light guide plate 10.
[0053] A difference in refractive index between the light guide
plate 10 and the low refractive layer 20 may be about 0.2 or more.
When the refractive index of the low refractive layer 20 is smaller
than the refractive index of the light guide plate 10 by about 0.2
or more, sufficient total reflection may occur at the upper surface
10a of the light guide plate 10. The difference in refractive index
between the light guide plate 10 and the low refractive layer 20
has no upper limit, but may be about 1 or less in consideration of
the refractive indices of the light guide plate 10 and the low
refractive layer 20 that are generally used.
[0054] The refractive index of the low refractive layer 20 may
range from about 1.2 to about 1.4. In general, when a refractive
index of a solid medium approaches 1, a manufacturing cost of the
solid medium exponentially increases. When the refractive index of
the low refractive layer 20 is about 1.2 or more, an excessive
increase in the manufacturing cost may be reduced or effectively
prevented. Also, the low refractive layer 20 may have a refractive
index of about 1.4 or less so as to sufficiently reduce a
total-reflection threshold angle of light at the upper surface 10a
of the light guide plate 10. In an exemplary embodiment, the low
refractive layer 20 may have a refractive index of about 1.25.
[0055] The low refractive layer 20 may include voids defined
therein to provide the above-described low refractive index. The
voids may be a vacuum, or may be filled with a medium such as air,
a gas and the like.
[0056] The low refractive layer 20 may cover most of the upper
surface 10a of the light guide plate 10 but may not overlap the
edge surface 10r of the light guide plate 10. That is, the edge
surface 10r is exposed to outside the light guide plate 10 by
termination of the low refractive layer 20 at a light incident edge
of the light guide plate 10. A side surface of the low refractive
layer 20 may be positioned further inward from the side surface
10s1 than the boundary between the upper surface 10a of the light
guide plate 10 and the edge surface 10r. In other words, the edge
surface 10r of the light guide plate 10 may protrude from the side
surface of the low refractive layer 20.
[0057] The low refractive layer 20 of the optical member 100 may be
formed by using a method such as coating and the like. In an
exemplary embodiment of manufacturing a display device, for
example, a material for forming a low refractive layer is
slit-coated on the upper surface 10a of the light guide plate 10
and then dried and cured to form the low refractive layer 20.
However, the method is not limited thereto, and various lamination
methods may be used.
[0058] The wavelength conversion layer 30 is disposed on the low
refractive layer 20. The wavelength conversion layer 30 converts a
wavelength of at least a part of incident light. The wavelength
conversion layer 30 may include a binder layer and wavelength
conversion particles which are distributed in the binder layer. The
wavelength conversion layer 30 may further include scattering
particles which are distributed in the binder layer in addition to
the wavelength conversion particles.
[0059] The wavelength conversion particles are particles which
convert a wavelength of incident light to a wavelength different
therefrom. In an exemplary embodiment, for example, the wavelength
conversion particles may be quantum dots ("QD"s), a fluorescent
material or a phosphorescent material.
[0060] The wavelength conversion particles may include a plurality
of wavelength conversion particles which convert a wavelength of
incident light into different wavelengths. In an exemplary
embodiment, for example, the wavelength conversion particles may
include first wavelength conversion particles which convert
incident light of a specific wavelength into a first wavelength and
emit the converted light of the first wavelength, and may include
second wavelength conversion particles which convert incident light
of the specific wavelength into a second wavelength and emit the
converted light of the second wavelength. In an exemplary
embodiment, light which is projected from the light source 400 and
incident on the wavelength conversion particles may be light of a
blue wavelength, the first wavelength may be a green wavelength,
and the second wavelength may be a red wavelength.
[0061] In the exemplary embodiment, while blue light incident on
the wavelength conversion layer 30 passes through the wavelength
conversion layer 30, a first portion of the blue light may be
incident on the first wavelength conversion particles, converted
into the green wavelength, and emitted from the wavelength
conversion layer 30. A second portion of the blue light may be
incident on the second wavelength conversion particles, converted
into the red wavelength, and emitted from the wavelength conversion
layer 30. A third (or remaining) portion of the blue light may not
be incident on the first and second wavelength conversion particles
to be emitted from the wavelength conversion layer 30 without being
converted to a different wavelength. Therefore, the light passing
through and emitted from the wavelength conversion layer 30
includes all light of the blue wavelength, the green wavelength and
the red wavelength. Where the light passing through and emitted
from the wavelength conversion layer 30 includes all the colored
light described above, display of white light or projection of
light of another color by appropriately adjusting a ratio of
emitted light of different wavelengths is possible. Most of the
light converted by passing through the wavelength conversion layer
30 is within a relatively small wavelength range and has a sharp
spectrum having a relatively small full width at half maximum.
Therefore, when color is finally implemented by filtering the light
having such a sharp spectrum such as with a color filter, color
reproduction at the optical member 100 may be improved.
[0062] Unlike the exemplary embodiment, incident light may be
relatively short-wavelength light, such as infrared rays and the
like. In this case, three wavelength conversion particles for
separately respectfully converting the short-wavelength light into
blue, green and red wavelengths may be disposed in the wavelength
conversion layer 30 and white light may be projected therefrom.
[0063] The wavelength conversion layer 30 may further include the
scattering particles. The scattering particles may be non-QDs which
do not have a wavelength conversion function. The scattering
particles may scatter light incident thereto so that more light may
be incident on the wavelength conversion particles. Also, the
scattering particles may serve to uniformly control projection
angles of wavelength-specific light. Specifically, green and red
wavelengths which are emitted after colliding with the wavelength
conversion particles may have a scattered emission characteristic,
where the scattering particles give the scattered emission
characteristic to a blue wavelength which travels through the
wavelength conversion layer 30 without colliding with the
wavelength conversion particles, such that projection angles of
wavelength-specific light may be adjusted to be similar to each
other. Materials such as TiO.sub.2, SiO.sub.2 and the like may be
used as the scattering particles.
[0064] The wavelength conversion layer 30 may cover an upper
surface of the low refractive layer 20 and completely overlap the
low refractive layer 20 in a top plan view. A lower surface of the
wavelength conversion layer 30 may come in direct contact with the
upper surface of the low refractive layer 20, such as to form an
interface therebetween. In an exemplary embodiment, an outer edge
of the side surfaces of the wavelength conversion layer 30 may be
aligned with an outer edge of the side surfaces of the low
refractive layer 20. The outer edge of the side surfaces of the
wavelength conversion layer 30 may be positioned further from the
side surface 10s1 than the boundary between the upper surface 10a
of the light guide plate 10 and the edge surface 10r thereof.
[0065] The wavelength conversion layer 30 of the optical member 100
may be formed by using a method such as coating and the like. In an
exemplary embodiment of manufacturing a display device, for
example, a material for forming wavelength conversion is
slit-coated on the light guide plate 10 on which the low refractive
layer 20 has been formed, and then dried and cured to form the
wavelength conversion layer 30. However, the method is not limited
thereto, and various lamination methods may be used.
[0066] The passivation layer 40 is disposed on the low refractive
layer 20 and the wavelength conversion layer 30. The passivation
layer 40 serves to reduce or effectively prevent infiltration of
moisture and/or oxygen (referred to as "moisture/oxygen" below)
other layers or components on the light guide plate 10. The
passivation layer 40 may include an inorganic material. In an
exemplary embodiment, for example, the passivation layer 40 may
include silicon nitride.
[0067] The passivation layer 40 may cover an upper surface of the
wavelength conversion layer 30 and completely overlap the
wavelength conversion layer 30. In an exemplary embodiment, the
passivation layer 40 completely covers the low refractive layer 20
and the wavelength conversion layer 30. The passivation layer 40
completely overlaps an upper surface of the wavelength conversion
layer 30 and further extends outward past the upper surface to
cover the side surfaces of the wavelength conversion layer 30 and
the side surfaces of the low refractive layer 20. The passivation
layer 40 may come in direct contact with the upper surface 10a of
the light guide plate 10. Side surfaces of the passivation layer 40
may be positioned further from the side surface 10s1 than the
boundary between the upper surface 10a of the light guide plate 10
and the edge surface 10r thereof. In other words, the passivation
layer 40 may not overlap the edge surface 10r of the light guide
plate 10.
[0068] However, the passivation layer 40 is not limited thereto,
and in some embodiments, the passivation layer 40 may not cover the
side surfaces of the low refractive layer 20 and/or the side
surfaces of the wavelength conversion layer 30.
[0069] The passivation layer 40 may be formed by using a method
such as deposition and the like. In an exemplary embodiment of
manufacturing a display device, for example, the passivation layer
40 may be formed on the light guide plate 10 on which the low
refractive layer 20 and the wavelength conversion layer 30 have
been formed in sequence, such as by using chemical vapor deposition
("CVD"). However, the method is not limited thereto, and various
lamination methods may be used.
[0070] As described above, the optical member 100 may
simultaneously perform a light guide function and a wavelength
conversion function as a single integrated member. Also, in the
optical member 100, the low refractive layer 20 is disposed on the
upper surface 10a of the light guide plate 10 so that total
reflection effectively occurs at the upper surface 10a of the light
guide plate 10. An increase in total reflection efficiency owing to
the low refractive layer 20 and the effective prevention of light
leakage owing to the inclined edge surfaces 10r of the light guide
plate 10 will be described below with reference to FIGS. 3 to
6.
[0071] FIG. 3 is a cross-sectional view of an exemplary embodiment
of region-specific threshold angles of a light guide plate within
an optical member according to the invention. FIG. 4 is a
cross-sectional view of paths of light at an edge portion of a
light guide plate within a conventional optical member and an
exemplary embodiment of an optical member according to the
invention. FIGS. 5A and 5B are graphs showing amounts of light
leakage caused by exemplary embodiments of an inclination angle and
a length of an edge surface in an optical member according to the
invention. FIG. 6 is a graph showing amounts of light leakage at a
boundary between exemplary embodiments of an edge surface and an
upper surface of a light guide plate in an optical member according
to the invention.
[0072] Referring to FIGS. 3 and 4, as described above, side
surfaces of the low refractive layer 20, side surfaces of the
wavelength conversion layer 30, and side surfaces of the
passivation layer 40 are each disposed further from the side
surface 10s1 than the boundary between the upper surface 10a and
the edge surfaces 10r of the light guide plate 10. In other words,
none of the low refractive layer 20, the wavelength conversion
layer 30 and the passivation layer 40 overlaps the edge surfaces
10r of the light guide plate 10. The edge surfaces 10r of the light
guide plate 10 may be exposed to an air layer outside the optical
member 100.
[0073] The edge surface 10r of the light guide plate 10 has optical
interfaces with the air layer outside the optical member 100. As
described above, the threshold angle .theta.t1 at the edge surface
10r of the light guide plate 10 may be about 42.degree.. In other
words, light which is incident on the edge surfaces 10r at an angle
of about 42.degree. or more may be totally reflected by the edge
surface 10r. As illustrated in FIG. 3, the threshold angle
.theta.t1 is defined relative to a line normal to the edge surface
10r.
[0074] On the other hand, the upper surface 10a of the light guide
plate 10 may come in direct contact with the low refractive layer
20. In an exemplary embodiment, for example, when the light guide
plate 10 has a refractive index of about 1.5 and the low refractive
layer 20 has a refractive index of about 1.25, a threshold angle
.theta.t2 at the upper surface 10a of the light guide plate 10 may
be about 57.degree.. In this case, it is possible to totally
reflect light which is incident on the upper surface 10a at an
angle of about 57.degree. or more. As illustrated in FIG. 3, the
threshold angle .theta.t2 is defined relative to a line normal to
the upper surface 10a.
[0075] In a conventional optical member, for example, a light guide
plate 10 may not include the edge surface 10r according to the
invention, and the side surface 10s1 and the lower surface 10b of
the light guide plate 10 may intersect each other at an angle of
about 90.degree., as indicated by the dotted line extensions of the
upper surface 10a, the lower surface 10b and the side surface 10s1
in FIG. 4. Since the lower surface of the light guide plate 10 in
the conventional optical member has an optical interface with the
air layer, a threshold angle may be about 42.degree. with respect
to the lower surface 10b of the light guide plate 10. As
illustrated in FIG. 4, first light L1, which is incident on the
lower surface 10b of the light guide plate 10 at an angle smaller
than the threshold angle, is not totally reflected within the
conventional optical member. Some rays of the first light L1 may be
projected through the lower surface 10b to be leaked, and other
rays of the first light L1 may be reflected and transmitted to the
upper surface 10a of the light guide plate 10. In this case, the
first light L1 is also incident on the upper surface 10a of the
light guide plate 10 at an angle smaller than the threshold angle
.theta.t2, and thus may be projected upward without being totally
reflected. In this way, when a large amount of light leaks upward
at the light incident surface 10s1 to which a large amount of light
is projected from the light source 400, light leakage may be
detected in a display screen.
[0076] On the other hand, second light L2 that is incident on the
light incident surface 10s1 of the light guide plate 10 in an
exemplary embodiment of an optical member at the same angle as the
first light L1 may have a larger incident angle than the threshold
angle .theta.t1. In other words, since one or more exemplary
embodiment of the optical member includes a light guide plate 10
defining the edge surface 10r inclined by the angle .theta.1 with
respect to the lower surface 10b, the second light L2 may have a
larger incident angle than the first light L1. Accordingly, the
second light L2 has a larger incident angle than the threshold
angle .theta.t1 at the edge surfaces 10r, and thus may be totally
reflected in the light guide plate 10. Therefore, in one or more
exemplary embodiment of the optical member according to the
invention, the amount of light that leaks to above the light guide
plate 10 (e.g., an emission side of the optical member) at the side
of the light incident surface 10s1 is reduced such that light
leakage may be reduced or effectively prevented and luminance
uniformity may be increased.
[0077] The inclination angle .theta.1 of the edge surfaces 10r may
be determined in consideration of the threshold angle .theta.t1 of
the light guide plate 10 with respect to the air layer and the
threshold angle .theta.t2 of the light guide plate 10 with respect
to the low refractive layer 20. In other words, since the threshold
angle .theta.t2 with respect to the low refractive layer 20 is
larger than the threshold angle .theta.t1 with respect to the air
layer, light has a larger incident angle than the threshold angle
.theta.t2 with respect to the low refractive layer 20 so that light
is effectively guided in the light guide plate 10.
[0078] In this regard, the inclination angle .theta.1 of the edge
surfaces 10r may be about 6.degree. to about 20.degree.. When the
inclination angle .theta.1 of the edge surfaces 10r is larger than
6.degree., a path of light may be effectively adjusted so that the
light has an incident angle larger than the threshold angle
.theta.t2 with respect to the low refractive layer 20. When the
inclination angle .theta.1 of the edge surfaces 10r is smaller than
20.degree., a path of light may be effectively adjusted while
ensuring a sufficient the planar area of the light incident surface
10s1 of the light guide plate 10. Also, light having incident
angles smaller than a threshold angle is concentrated at the light
incident surface 10s1. In consideration of the inclination angle
.theta.1 of the edge surfaces 10r, a distance sufficient for
changing paths of the light having relatively small incident angles
is possible when the distance d1 from the light incident surface
10s1 to the boundary between the edge surfaces 10r and the
upper/lower surface 10a/10b is about 0.84 mm or more. In an
exemplary embodiment, the distance d1 from the light incident
surface 10s1 to the boundary between the edge surfaces 10r and the
upper/lower surface 10a/10b is about 1 mm or more.
[0079] To experimentally confirm an improvement in light leakage
caused by the edge surfaces 10r, as an exemplary embodiment
according to the invention a glass light-guide plate 10 having a
thickness of 1.1 mm and including the edge surfaces 10r was
prepared. As a comparative example, a glass light-guide plate that
did not have the edge surfaces 10r and had an upper/lower surface
intersecting side surfaces at right angles was prepared. FIG. 5A is
a graph showing results of measuring the amounts of light projected
upward at the light incident surface 10s1 when the respective
exemplary embodiment and comparative light guide plates were used.
FIG. 5B is an enlarged portion of the graph of FIG. 5A showing
various exemplary embodiments of an optical member according to the
invention. FIG. 6 is a graph showing the amounts of upward light
leakage at the light incident surface 10s1 when the respective
light guide plates were used.
[0080] Referring to FIGS. 5A and 5B, the (horizontal) x-axis of the
graph denotes a relative distance (in mm) of a light incident
surface edge portion from an active area of a light guide plate,
and the y-axis denotes the amount of output light (in percent %)
according to the height h1 (refer to FIG. 2) of the edge surface
10r and the length d1 (refer to FIG. 2) of the section occupied by
the edge surface 10r. It is possible to see that the amount of
light projected upward at the light incident surface 10s1 was
reduced in the light guide plate 10 including the edge surfaces 10r
("ChamperXmm/SECTION Ymm" lines) in comparison to that in the light
guide plate not including the edge surfaces 10r ("offset 3 mm"
line"). Specifically, it is possible to see that the least amount
of light was projected above the light guide plate 10 at the light
incident surface 10s1 when the height h1 of the edge surfaces 10r
was 0.1 mm and the length d1 was 3 mm in an exemplary embodiment of
an optical member according to the invention.
[0081] Referring to the graph of FIG. 6, the height h1 of the edge
surface 10r was 0.1 mm or 0.2 mm in exemplary embodiments of an
optical member according to the invention. Amounts of light leakage
at the light incident surface 10s1 of the light guide plate 10 are
shown as relative values along the y-axis, while the length d1 of
the section occupied by the edge surfaces 10r varied between 1 mm
to 3 mm in combinations with the height h1 are shown along the
x-axis. It is possible to see that the amount of light leakage was
reduced in the light guide plate 10 in exemplary embodiments of an
optical member according to the invention ("0.X/Ymm" bars) in
comparison to that in the light guide plate according to a
comparative example ("Ref" bar) not including the edge surface 10r.
Specifically, the most effective improvement in light leakage
occurred when the height h1 of the edge surface 10r was 0.1 mm and
the length d1 was 3 mm in the exemplary embodiment of the optical
member according to the invention.
[0082] As described above, one or more exemplary embodiment of the
light guide plate 10 including the edge surface 10r may reduce or
effectively prevent light leakage and increase luminance uniformity
of an optical member by improving total reflection efficiency.
[0083] Other exemplary embodiments of an optical member will be
described below. Descriptions of elements identical to those
described above will be omitted or given briefly, and differences
will be mainly described.
[0084] FIGS. 7 to 9 are cross-sectional views of modified exemplary
embodiments of an optical member according to the invention. The
exemplary embodiments of FIGS. 7 to 9 illustrate that the shapes
and arrangement of respective elements of an optical member may be
variously modified.
[0085] FIG. 7 illustrates that the edge surfaces 11r of a light
guide plate 11 in the optical member 101 may be a curved surface in
cross-section. In other words, the edge surface 10r of the light
guide plate 10 in the optical member 100 of FIG. 2 differs from the
edge surface 11r of FIG. 7 in that edge surface 10r is a flat
surface in cross-section. The light guide plate 11 may further
include or define an upper surface 11a, a lower surface 11b, a
light incident side surface 11s1 and a light-facing side surface
11s3.
[0086] The shapes of the edge surface 11r of the light guide plate
11 may be variously modified as long as a path of light changed by
the edge surface 11r satisfies a total reflection angle.
[0087] FIG. 8 illustrates that a side surface 22s of a low
refractive layer 22, a side surface 32s of a wavelength conversion
layer 32, and a side surface 42s of a passivation layer 42 may be
aligned with (e.g., coplanar with) an edge surface 12r of a light
guide plate 12. In this case, the passivation layer 42 may cover
neither the side surface 22s of the low refractive layer 22 nor the
side surface 32s of the wavelength conversion layer 32 at a light
incident surface 12s1 end portion of the light guide plate 12. The
light guide plate 12 may further include or define an upper surface
12a, a lower surface 12b and a light-facing side surface 12s3.
[0088] The side surface 22s of the low refractive layer 22 may be
aligned at a boundary between the edge surface 12r and an upper
surface 12a of the light guide plate 12. An inclination angle of
the side surface 22s of the low refractive layer 22 may be
substantially the same as an inclination angle .theta.1 of the edge
surface 12r. In other words, the side surface 22s of the low
refractive layer 22 may be disposed in substantially the same plane
as the edge surface 12r.
[0089] The side surface 32s of the wavelength conversion layer 32
may be disposed further from the light incident surface 12s1 than
the boundary between the edge surface 12r and the upper surface 12a
of the light guide plate 12. The side surface 32s of the wavelength
conversion layer 32 may be substantially aligned with a boundary
between the side surface 22s and an upper surface of the low
refractive layer 22. An inclination angle of the side surface 32s
of the wavelength conversion layer 32 may be substantially the same
as the inclination angle .theta.1 of the edge surface 12r. In other
words, the side surface 32s of the wavelength conversion layer 32
may also be disposed in substantially the same plane as the edge
surface 12r.
[0090] The side surface 42s of the passivation layer 42 may be
disposed further from the light incident surface 12s1 than the
boundary between the edge surface 12r and the upper surface 12a of
the light guide plate 12. The side surface 42s of the passivation
layer 42 may be substantially aligned with a boundary between an
upper surface and the side surface 32s of the wavelength conversion
layer 32. An inclination angle of the side surface 42s of the
passivation layer 42 may be substantially the same as the
inclination angle .theta.1 of the edge surface 12r. In other words,
the side surface 42s of the passivation layer 42 may also be
disposed in substantially the same plane as the edge surface
12r.
[0091] In an exemplary embodiment of manufacturing an optical
member, a structure such as an optical member 102 of FIG. 8 may be
obtained by stacking the low refractive layer 22, the wavelength
conversion layer 32 and the passivation layer 42 on the light guide
plate 12 to have ends corresponding to the light incident surface
12s1 and then cutting off the light guide plate 12 to form the edge
surface 12r. In other words, the side surface 22s of the low
refractive layer 22, the side surface 32s of the wavelength
conversion layer 32 and the side surface 42s of the passivation
layer 42 may be cut surfaces obtained together with the edge
surface 12r when portions of the layers are removed from the
originally-stacked structure.
[0092] An optical member 103 of FIG. 9 illustrates that a second
edge surface 13r2 may also be disposed or formed at a light-facing
surface 13s3 of the light guide plate 13.
[0093] The light guide plate 13 may include a first edge surface
13r1 disposed or formed at a light incident surface 13s1 and
further include the second edge surface 13r2 disposed or formed at
the light-facing surface 13s3. The second edge surface 13r2 may be
disposed or formed not only between the light-facing surface 13s3
and an upper surface 13a but also between the light-facing surface
13s3 and a lower surface 13b. Although not shown in the drawing, an
edge surface may also be formed at other side surfaces (e.g., like
10s2 and 10s4 relative to 10s1 and 10s3 in FIG. 1) of the light
guide plate 13.
[0094] An inclination angle of the second edge surface 13r2 may be
the same as or different from an inclination angle .theta.1 of the
first edge surface 13r1.
[0095] FIG. 9 further illustrates that a side surface 23s of a low
refractive layer 23, a side surface 33s of a wavelength conversion
layer 33, and a side surface 43s of a passivation layer 43 may be
aligned with (e.g., coplanar with) edge surfaces 13r1 and/or 13r2
of the light guide plate 13. In this case, the passivation layer 43
may cover neither the side surface 23s of the low refractive layer
23 nor the side surface 33s of the wavelength conversion layer 33
at the light incident surface 13s1 or the light-facing surface 13s3
end portions of the light guide plate 13.
[0096] Since the edge surfaces 13r1 and 13r2 adjust a path of light
and also reduce or effectively prevent breakage of corners of the
light guide plate 13 during manufacturing of an optical member, the
light guide plate 13 may have excellent durability.
[0097] FIGS. 10 to 12 are cross-sectional views of other exemplary
embodiments of optical members according to the invention. The
exemplary embodiments of FIGS. 10 to 12 illustrate that an optical
member may further include a light adjustment member.
[0098] FIG. 10 illustrates that a light guide plate 14 of an
optical member 104 may not include an edge surface defined by a
body of the light guide plate 14. In other words, a plane in which
the upper/lower surface 14a/14b of the light guide plate 14 is
positioned may be inclined by about 90.degree. with respect to a
plane in which a side surface 14s is positioned (e.g., such as the
light incident surface 14s1 and a light-facing surface 14s3).
[0099] The upper surface 14a of the light guide plate 14 may be
divided into a first region that is relatively adjacent to the
light incident surface 14s1 and a second region that is relatively
adjacent to the light-facing surface 14s3. A low refractive layer
20, a wavelength conversion layer 30 and a passivation layer 40 may
be disposed on the second region of the upper surface 14a of the
light guide plate 14, and a light adjustment member 80 may be
disposed on the first region. The light adjustment member 80 may
come in direct contact with the upper surface 14a of the light
guide plate 14 in the first region. On the other hand, in the
second region, the low refractive layer 20, the wavelength
conversion layer 30, and the passivation layer 40 may be disposed
between the light adjustment member 80 and the light guide plate
14. Outer edges of the low refractive layer 20, the wavelength
conversion layer 30, the passivation layer 40 and/or the light
adjustment member 80 may define a boundary between the first and
second regions.
[0100] The light adjustment member 80 may be disposed not only at
the upper surface 14a but also on the lower surface 14b of the
light guide plate 14. The light adjustment members 80 disposed on
the upper surface 14a and the lower surface 14b may have generally
symmetric shapes with respect to the light guide plate 14
therebetween.
[0101] The light adjustment members 80 may come in direct contact
with the upper surface 14a and the lower surface 14b of the light
guide plate 14. Refractive indices of the light adjustment members
80 may be the same as or higher than a refractive index of the
light guide plate 14. In an exemplary embodiment of manufacturing
an optical member, for example, when the light adjustment members
80 are formed by imprinting, a resin material having a refractive
index that is the same as or higher than the refractive index of
the light guide plate 14 may be used. In an exemplary embodiment of
manufacturing an optical member, the light adjustment member 80
formed on the lower surface 14b of the light guide plate 14 may be
formed together with a scattering pattern 70 such as at a same
time, in a same process and or from a same material layer.
[0102] In a conventional optical member, when the refractive
indices of the light adjustment members 80 are the same as the
refractive index of the light guide plate 14, boundaries between
the light adjustment members 80 and the light guide plate 14 are
not recognized as optical interfaces, and thus light may be
incident onto the light adjustment members 80 without being
reflected or refracted at the boundaries. In one or more exemplary
embodiment of an optical member according to the invention, when
the refractive indices of the light adjustment members 80 are
higher than the refractive index of the light guide plate 14,
upper-surface threshold angles of the light adjustment members 80
exposed to the air layer further increase, and thus more effective
optical interfaces are formed.
[0103] The light adjustment members 80 may lengthwise extend in a
longitudinal direction along a length of the side surface 14s1 of
the light guide plate 14. Heights of the light adjustment members
80 along a thickness direction (e.g., vertical in FIG. 10) may
generally increase in a direction from the side surface 14s1 of the
light guide plate 14 toward the inside of the light guide plate 14
(e.g., toward the light-facing surface 14s3). In other words, a
vertical distance from the upper surface 14a of the light guide
plate 14 to an upper surface of the light adjustment member 80 may
increase in a direction from the side surface 14s1 of the light
guide plate 14 toward the inside of the light guide plate 14. The
maximum vertical distance from the upper surface 14a of the light
guide plate 14 to the upper surface of the light adjustment member
80 may be substantially the same as a height from the upper surface
14a of the light guide plate 14 to an uppermost surface of the
passivation layer 40. However, the vertical distance is not limited
thereto, and the light adjustment member 80 may be disposed or
formed to protrude further from the uppermost surface of the
passivation layer 40.
[0104] The light adjustment members 80 may perform a function
similar to that of the edge surfaces 10r defined by a body of the
light guide plate 10 (refer to FIGS. 1-4). In other words, the
light adjustment members 80 may adjust a path of light incident to
the light guide plate 14 to increase total reflection efficiency in
the light guide plate 14 and to reduce or effectively prevent light
leakage at the light incident surface 14s1. It is considered that a
collective light guide member may include the light guide plate 14
and the light adjustment members 80, when an inclined edge surface
of such light guide member is defined by the light adjustment
members 80.
[0105] Specifically, since the upper surface of the light
adjustment member 80 is inclined with respect to the upper surface
14a of the light guide plate 14, an incident angle .theta.3 of
light L4 with respect to the upper surface of the light adjustment
member 80 may be larger than an incident angle .theta.2 of light L3
with respect to the upper surface 14a of the light guide plate 14.
In other words, even when the incident angle .theta.2 with respect
to the upper surface 14a of the light guide plate 14 is smaller
than a threshold angle, the incident angle .theta.3 with respect to
the upper surface of the light adjustment member 80 may be larger
than a threshold value. In this case, even when the third light L3
and the fourth light L4 are incident at the same angle from the
light source 400, the third light L3 has the incident angle
.theta.2 smaller than the threshold angle of the upper surface 14a
of the light guide plate 14 and thus goes through the upper surface
14a light guide plate 14, whereas the fourth light L4 has the
incident angle .theta.3 larger than the threshold angle of the
upper surface of the light adjustment member 80 and thus may be
totally reflected back into the light guide plate 14. In this way,
the light adjustment members 80 may perform a function
substantially similar to that of the edge surfaces 10r of the light
guide plate 10.
[0106] FIG. 11 illustrates that a light guide plate 15 of an
optical member 105 may include edge surfaces 15r. The light guide
plate 15 may further include or define an upper surface 15a, a
lower surface 15b and a light-facing side surface 15s3.
[0107] Light adjustment members 81 may be respectively disposed on
the edge surfaces 15r of the light guide plate 15. The light
adjustment members 81 may cover the edge surfaces 15r and
compensate for a planar area of a light incident surface 15s1
defined by a body of the light guide plate 15 which is reduced by
the edge surfaces 15r.
[0108] Specifically, a height h2 of the light incident surface 15s1
of the light guide plate 15 is reduced by double a height h3 of the
edge surfaces 15r. In this case, the planar area of the light
incident surface 15s1 is reduced, and the amount of light incident
into the light guide plate 15 may be reduced. The light adjustment
members 81 may increase the planar area of a total light incident
surface of the light guide plate 15 by compensating for height
differences caused by the height h3 of the edge surfaces 15r.
Accordingly, the degree of freedom in selecting an inclination
angle and the height h3 of the edge surfaces 15r may increase
regardless of the planar area of the light incident surface 15s1
defined by a body of the light guide plate 15.
[0109] Referring to FIG. 12, side surfaces of a low refractive
layer 26, a wavelength conversion layer 36 and a passivation layer
46 of an optical member 106 may be aligned with (e.g., coplanar
with) an edge surface 16r of a light guide plate 16. The light
guide plate 16 may further include or define an upper surface 16a,
a lower surface 16b, a light incident surface 16s1 and a
light-facing side surface 16s3.
[0110] A light adjustment member 82 may cover the edge surface 16r
and further extend inward to cover the side surfaces of the low
refractive layer 26, the wavelength conversion layer 36 and the
passivation layer 46. In this exemplary embodiment, the passivation
layer 46 does not cover side surfaces of the wavelength conversion
layer 36 and the low refractive layer 26, but the light adjustment
member 82 instead covers the side surfaces of the wavelength
conversion layer 36 and the low refractive layer 26 such that a
sealed structure may be maintained. Therefore, durability of the
wavelength conversion layer 36 is improved by reducing of
preventing infiltration of moisture/oxygen into the wavelength
conversion layer 36.
[0111] FIG. 13 is a cross-sectional view of still another exemplary
embodiment of an optical member according to the invention.
[0112] Referring to FIG. 13, an optical member 107 may further
include an angle filter 90.
[0113] The angle filter 90 may be disposed on a light incident
surface 17s1 of a light guide plate 17. Among rays of light
projected from a light source 400, the angle filter 90 reflects
rays of light having an incident angle larger than a first angle
with respect to the light incident surface 17s1 and passes rays of
light having an incident angle smaller than the first angle. In
other words, rays of light having an incident angle smaller than a
threshold angle of an upper/lower surface 17a/17b of the light
guide plate 17 are filtered before being incident into the light
guide plate 17, and rays of light having an incident angle larger
than the threshold angle of the upper/lower surface 17a/17b are
passed through the light incident surface 17s1 opposite to the
light-facing surface 17s3, such that total reflection efficiency in
the light guide plate 17 may be increased.
[0114] In consideration of the threshold angle of the upper/lower
surface 17a/17b of the light guide plate 17, the first angle may be
about 54.degree.. In other words, light having an incident angle
larger than about 54.degree. with respect to the light incident
surface 17s1 of the light guide plate 17 may be reflected, and
light having an incident angle smaller than about 54.degree. may be
passed through the angle filter 90 and incident onto the light
guide plate 17.
[0115] The light source 400 may further include a reflection member
700. The reflection member 700 re-reflects light reflected by the
angle filter 90 and causes the light to be incident onto the light
guide plate 17. Light reflected by the reflection member 700 has an
incident angle smaller than the first angle and may pass through
the angle filter 90. The reflection member 700 may increase light
incident efficiency by reusing light that has not entered the light
guide plate 17, and may reduce or effectively prevent light leakage
at the light incident surface 17s1.
[0116] The optical members 100 to 107 according to the various
exemplary embodiments described above may be applied to display
devices, lighting fixtures and the like, to generate and provide
light. A display device including an optical member will be
described in detail below.
[0117] FIG. 14 is a cross-sectional view of an exemplary embodiment
of a display device according to the invention.
[0118] Referring to FIG. 14, a display device 1000 includes a light
source 400, an optical member 100 disposed in a light projection
(emission) path of the light source 400, and a display panel 300
disposed over the optical member 100.
[0119] Any of the optical members 100 to 107 and features thereof
according to the above-described exemplary embodiments may be used.
FIG. 14 illustrates a case in which the optical member 100 of FIG.
2 used.
[0120] The light source 400 is disposed at a side of the optical
member 100. The light source 400 may be disposed adjacent to the
light incident surface 10s1 of the light guide plate 10. The light
source 400 may include a point light source or a linear light
source provided in singularity or plurality. The point light
sources may be a plurality of the LED light source 410. The
plurality of LED light sources 410 may be mounted on the PCB 420.
The LED light sources 410 may generate and emit light of a blue
wavelength.
[0121] The display device 1000 may further include a reflection
member 250 disposed under the optical member 100. The reflection
member 250 may include a reflection film or a reflection coating
layer. The reflection member 250 reflects light projected through
the lower surface 10b of the light guide plate 10 in the optical
member 100 and causes the light to re-enter the light guide plate
10.
[0122] The display panel 300 is disposed over the optical member
100. The display panel 300 receives light from the optical member
100 and displays a picture or image with the received light. The
display panel 300 may be a liquid crystal display ("LCD") panel,
but is not limited thereto.
[0123] The display panel 300 may include a first (display)
substrate 310, a second (display) substrate 320 opposite to the
first substrate 310, and an optical transmittance layer such as a
liquid crystal layer (not shown) disposed between the first
substrate 310 and the second substrate 320 and with which light is
transmitted or blocked.
[0124] The optical member 100 may be coupled with the display panel
300 through inter-module coupling member 611. The inter-module
coupling member 611 may have a rectangular frame shape in a plan
view. The inter-module coupling member 611 may be positioned at
respective edge portions of the display panel 300 and the optical
member 100. The inter-module coupling member 611 may be disposed to
not overlap the edge surfaces 10r of the light guide plate 10, and
the edge surfaces 10r may be exposed to an air layer outside of the
optical member 100.
[0125] The inter-module coupling member 611 may include a polymer
resin, an adhesive or viscous tape, or the like.
[0126] The display device 1000 may further include a housing 500 in
which other components of the display device 1000 are accommodated.
The housing 500 has one open side at an upper portion thereof, and
includes a bottom surface 510 and a sidewall 520 which is connected
to the bottom surface 510. The light source 400, the optical member
100, the display panel 300, the inter-module coupling member 611,
and the reflection member 250 may be contained in a space defined
by the bottom surface 510 and the sidewall 520 of the housing
500.
[0127] The display device 1000 may further include at least one
optical film 200. The at least one optical film 200 may be
contained in a space surrounded by the inter-module coupling member
611 and defined between the optical member 100 and the display
panel 300.
[0128] The optical film 200 may include one or more individual film
such as a prism film, a diffusion film, a microlens film, a
lenticular film, a polarizing film, a reflective polarizer film, a
phase difference film and the like, but is not limited thereto.
[0129] In the display device 1000 according to an exemplary
embodiment of FIG. 14, the optical member 100, the display panel
300, and even the optical film 200 are integrated by the
inter-module coupling member 611, and the display panel 300 and the
housing 500 are coupled together by a housing coupling member 620.
Therefore, even when a mold frame of a convention display device is
omitted, several members of the display device 1000 are stably
coupled together, such that the display device 1000 may be reduced
in overall weight. Also, since the light guide plate 10 and the
wavelength conversion layer 30 are integrated into a single optical
member 100 which performs a light guiding function and a wavelength
converting function, the display device 1000 may be reduced in
overall thickness. Further, a side surface of the display panel 300
and the sidewall 520 of the housing 500 are coupled together by the
housing coupling member 620, and thus a total planar area of a
bezel at a display side of the display device 1000 is minimized or
removed entirely.
[0130] The effects according to one or more exemplary embodiment of
the present disclosure are as follows.
[0131] An optical member according to one or more exemplary
embodiment according to the invention can perform a light guide
function exhibiting an excellent straight-line travel
characteristic of light.
[0132] Effects of exemplary embodiments are not limited to the
aforementioned example, and various effects are included in this
specification.
[0133] Although exemplary embodiments of the present disclosure
have been described above with reference to the accompanying
drawings, those of ordinary skill in the technical field to which
the present disclosure pertains will appreciate that the
embodiments may be implemented in other concrete forms without
changing the technical spirit or essential features of the present
disclosure. Therefore, the above-described embodiments are to be
understood as exemplary rather than limiting in all features.
* * * * *